It is with great regret that I inform you of a revision to the grade you received in Constitutional Law 101 as a first-year student here at Duke University School of Law. I have changed it to an “F.”

You really left me no choice in this matter, given your recent bizarre assertion that as New York’s attorney general, you would have the authority to prosecute federal law-enforcement agents for enforcing federal immigration law.

Perhaps your volunteer work for Howard Dean’s presidential campaign kept you from class the day we covered Clause 2 of Article VI of the Constitution? That’s the provision that states:

This Constitution, and the Laws of the United States, which shall be made in Pursuance thereof…shall be the supreme Law of the Land; and the Judges in every State shall be bound thereby, any Thing in the Constitution or Laws of any State to the Contrary notwithstanding.

As your classmates learned that day, this is what is known in legal circles as the “supremacy clause.” It specifies that federal law takes precedent over state law, and it “binds all legal actors,” which would include even the attorney general of the state of New York.

Perchance you also missed our discussion of one of the U.S. Supreme Court’s most famous decisions: McCulloch v. Maryland (1819). That’s the one where the Court held that Maryland could not constitutionally tax the operations of the Bank of the United States due to the supremacy clause. As Chief Justice John Marshall wrote, “It is the very essence of supremacy to remove all obstacles to its action within its own sphere, and so to modify every power vested in subordinate governments, as to exempt its own operations from their own influence.”

In other words, the operations of the federal government, which clearly include the enforcement of federal law, are exempt from interference by state governments.

Then, of course, there’s that pesky little third clause of Article VI. It provides that all legislative, executive, and judicial officers of “both the United States and of the several States, shall be bound by Oath or Affirmation, to support this Constitution.” As even a first-year law student should understand, this means that an individual elected to be the attorney general of any state must swear an oath to support the Constitution. That would include Article VI and the supremacy clause.

I don’t wish to belabor this point, but I do very much want to repair this apparent deficit in your Con Law educational experience. The plain fact is: a state attorney general cannot prosecute a federal law-enforcement officer for carrying out his duty to enforce federal law. This includes the agents of the Immigration and Customs Enforcement Agency. Any state attorney general who attempts to do so would be in violation of her oath to support the Constitution of the United States.

For a case directly on point, please see Cunningham v. Neagle (1890). In that case, the State of California tried to prosecute Deputy U.S. Marshal David Neagle for murder.

Neagle was assigned to protect U.S. Supreme Court Justice Stephen J. Field as he rode circuit in California. David Terry — a former Confederate Army officer and former California Supreme Court Justice — attacked Field on a train. Neagle then shot and killed Terry.

The Supreme Court held that California could not prosecute a U.S. marshal for carrying out his duty, under federal law, to protect a justice. Similarly, New York cannot criminally prosecute ICE agents for carrying out their duties under federal immigration law.

I am afraid that I have no choice but to fail any law student who does not know, recognize, or understand the importance and implications of the supremacy clause as a basic tenet of constitutional law that governs our federal system.